Gas operated automatic firearm



Sept. 21, 1937.

M, A. BRowNlNG I GAS vOPERTED AUTOMATIC FIREARM original Filed April 1o. -1934 rngy UNITED STATES PATENT oEElcE Patented Sept. 21, 1937 GAS OPERATED AUTOMATIC FIREARM Marriner A. Browning, Ogden, Utah, assignor to J. M. & M. S. Browning Company, Ogden, Utah, a corporation o! Utah Original application April 10, 1934, Serial No.

mit the barrel to be disconnected from the casing able tool such as the head of a cartridge and 5 of the gun. thenthe barrel can -b turned in the clockwise This present application constitutesa division direction to disengage the interrupted threads' at of my copending application for Automatic fire- III.V This permits the barrel to be drawn out in arm, Serial No. 719,862, led April 10, 1934. the forward direction. In order toy avoid the In the accompanying drawing I have shown necessity for using a tool to replace the'barrel. 10 the embodiment of the invention which I now the barrel is provided, as shown in Fig. 4, withV a e deem preferable, but it will be understood that longitudinal groove I5 positioned to receive and the drawing is intended lfor illustrative purposes provide clearance for the pin Thegroove I6 only and is not to be relied upon as limiting or has a beveled surface I6* adjacent its forward dening the scope of the invention, the claims end, which surface serves to cam the pin out'- 15 forming a part of this speciilcation being relied ward when the barrel is moved in= the counterupon for that purpose. l clockwise direction -into locking position.' As

Of the drawing: soon'as locking p'osition is reached the piny Fig. 1 is a side View of a firearm embodying the snaps into the hole in the barrel, thus firmly invention. locking it. A y r 20 Fig. 2 is an enlarged fragmentary view of the 'I'he barrel 2 may be-providedwith a'seriesof front portion of the iirearm, this view being partannular ribs to facilitate cooling," but such ribs ly a side view and partly a longitudinal sectional are not shown. As already explained the barrel view. is readily removable, and if excessive heating Fig. 3 is a view similar to Fig. 2, but showing eventually occurs the gun may be kept inservice 25 the parts in different relative positions. by removing one barrel and substituting another. 1

Fig. 4 is a fragmentary perspective view of the 'The casing I is provided .with an integral ex-` rear portion of the barrel. I tension |e which extends forward underneath Fig. 5 is a transverse sectional view taken the barrel. This extension is hollow and itserves along the line 5-5 oi' Fig. 2. to engage and retain a -gas conducting means 30 Fig. 6 is a fragmentary longitudinal sectional which may take the form of a piston tube such view of the rear portion ofA the firearm showing as illustrated at I6. The tube I6 is-preferably the breech bolt in an intermediate position. supported by the casing so as to be slidable longi- Referring to the drawing, I represents as an tudinally with respect'thereto, andit'smovemen't 30 entirety the main breech casing, which is generisguided in part by a removable pin II in the casl35 ally rectangular in transverse section. The poring extending through a longitudinal slot in the tion I of the casing near the front is 'formed'to rearward extending portion I6'l of the tube. `In receive the rear end of a barrel 2. Contained addition there is preferably a lip `I6b on the tube within the casing lare feeding and ring mechaextension slidably engaging the wall of a recess 40 nisms to which the present invention does not I8 inthe plate 6. At its forward end the tube I6 40 particularly relate. The detalls of these mechais connected with and supported by the barrel.4 nisms are disclosed in my aforesaid application The front end of the tubeis closed by a plug |6d Serial No. r119,862. The casing ,I is closed at the which is held by threads and is provided with one rear by a plate 1, which carries the trigger 8 and or more radial 'gas holes I6 adapted to register 40 control handles 9, 9. The plate 1 with the parts with a hole I6t in the topv of the tube. Preferably 45- thereon is readily removable. the tube is provided at the top thereof with a pro- The barrel 2 is preferably detachably connected jection I9 having a T-shaped slot'therein which with the casing and has a rear cylindrical portion rits a T-shapedr projection on the barrel.y With 2a which fits a cylindrical hole in the portion I* the parts engagedas shown in Figs. 2 and 5 the of the casing. The rear end of the barrel is protube is held in rigid' relationship tothe barrel, 50

vided at I0 with interrupted external threads with the hole I6t in thetube inv register with a'Ik adapted to engage similar internal threads radial gas hole 2b in the barrel. By means of. the formed in the casing. When the barrel is in the holes 2b, I6t and -||e the gases of explosion 'can v position shown in Figs. 2 and 3 it is firmly held enter the gas tube I6. By moving the tube rearin place by the threads. It can be released by ward it is disengaged `from the barrel as shown being turned through a quarter turn in the clockin Fig. 3,'thus leaving the barrel'free to be turned' wise direction. The barrel is normally held in so that it may be disengagedirom the casing in its locked position by means of a pin I held by the manner already explained;

a spring I2. The rear end of the spring is T- The tube I6 is normally-held in its forwarden- 719,862.` Divided and this application Marchv 19, 1935, Serial No. 111,790

s claims.

y The invention relates particularly to a gas ciperated rearm having the piston tube normally connected with the barrel and readily movable rearward to disengage the barrel and to thus pershaped and fits a T-shaped'groove I3 in the top oi.'

the casing', and a screw Il normally serves to p'revent the spring from movingrearward out oi the T-shaped slot. The-'pin II can be I withdrawn from the hole in the barrel bymeans of a suitgaged position by means of two links 2| and k22l which are pivotally connected with each other by a pin 23. Preferably the link 2| is U-shaped in cross section so as to partly surround and enclose the link 22. 'I'he link 2| is pivoted to the front end of the portion I ofl the casing by means of a removable pin 24, and the link 22 is pivotedk to the tube I6 by means of a pin 25. A

spring pressed latch 26 is provided for holdingY the link 2| in its upper or normal position. It will be observed that with therparts inthe positions shown in Fig. 2 the `tube I6 is held in its forward position, the link 2| substantially enclosing the link 22. When it is desired to move the tube I6 in the rearward direction the link 2| isy disengaged 'from the latch 26 and the link is moved downward to the position shown in Fig. 3, thus drawingy the tube rearward andn disengaging the projection IS from the Trshaped projectionon the barrel. Y Y

Longitudinally lmovable along the'bottom vof the main casing is an operating slide 21, this slide being connected with a pistonl rod 28 and a piston 29 positioned within the piston tube IS. The operating slide 21 is considerably wider than the piston rod 28 -and is bifurcatedY to receive the rearward end of the piston rod which is connected thereto -by the pin 30. This difference in width results in the formation ofthe shoulders 21 on the operating slide at the opposite sides of the piston rod. Preferably the piston 29 is formed integrally with the rod and consists of one or more annularflanges thereon. A cylinder 3| is provided in the forward end of the tube I6, being held in place by threads, and the piston 29 accurately fits the said cylinder. Although not essential to the invention, the cylinder is shown as an integral part of the plug IId. The before mentioned series of registering gas holes connect the bore of the barrel 2 with the interior of the cylinder 3| in order that a portion of the gases of explosion may enter the cylinder and act upon the` piston 29 to force it rearward. It is apparent that the .flow of gas through the gas conducting means may be regulated by varying the adjustment of the member Id to thereby bringa diiferent sized hole I6 into alignment with-thel hole |61. It should be noted that with my construction the adjustingmeans Iiid may be located at the forward end ofthe tube I6 so as to be readily accessible.

For returning the slide` 21 in the forward direction after it has been moved `rearward by the piston and piston rod there is provided asuitable action spring, which is not shown but which is preferably located near the rear of the casing I. It will be understood that the slide 21, during its rearward movement caused by the pressure of the gases and during its return movement caused by the spring, serves to operate the feeding` and firing mechanisms of the gun. l

In Fig.- 2 the breech bolt 45 is shown in its forward position, with the extractor 69 thereon entered in a notch in the barrel and in position toA engage a cartridge shell in the chamber.. In this position the extractor would prevent -removal of the barrel and no attempt should be made to remove it with the parts in this position. .Ordinarily and preferably when the tube I6 is tov be movedrearward as shown in Fig. 3 preliminarily to removing the barrel, the slide 21 and the piston rod 28 are in their rearward positions as shown in the same figure.

ever, that'the slide and the piston rod are permittedto remain in their lforward positions as shown in Fig. 2 a shoulder I 6 on the tube I6 In the event, how- Y engages the shoulders 21'l at the forward end of the slide 21, thus causing the slide Vto move rearward as the tube moves. 'This rearward movement of the slide serves by means of the links 46 and 41 as shown in Fig. 6, to move the breech bolt Il' rearward to a suillcient extent to withdraw the extractor B9 from the barrel notch 1I. I'his prevents any injury to the extractor 69, even though the slide and bolt have not been moved to their rearward positions prior to the t operations incident to the removal of the barrel.

. Preferably the slide 21 and some of the parts associated therewith, including the piston rod and the piston, are removable from the firearm at the rear thereof. To effect such removal it is necessary to remove the plate 1 with the parts carried thereby.

Y What I claim is: l

d 1. Inagas operated rearm, the combination of a mainY casing having breech mechanism therein, a barrel at the front of the casing, cooperating means on the casing and barrel forsecuring the latter to the former but permitting the removal ofthe barrel upon relative rotation of the two, gas conducting means slidably supported by the casing and having a gas hole in the top thereof registering with a gas hole in the barrel when the gas conducting means is in its normal forward position, means supported solely by the gas conducting means for closing the forward end thereof, movable gas operated means for actuating the breech mechanism, and cooperating Vmeans on the gas conducting means and barrel,

for slidably connecting the two and for preventing rotation of the barrel relative to the casing when said gas conducting means is in its normal position, the gas conducting means being movable rearward from normal position to disconnect the same from the barrel to permit rotation of the latter relative to the casing.

2. In a gasv operated rearm, the combination of a main casing having breech mechanism therein, a barrel at the front of the casing, cooperating means on the casing and barrel for securing the latter to the former but permitting the removal of the barrel upon relative rotation of the two, gas conducting means slidably supported by the casing and having a gas hole in the top thereof registering with a gas hole in the barrel when the gas conducting means is in its normal forward position, means supported solely by the gas conducting means for closing the forward end thereof and including adjustable means readily accessible from the forward end for regulating the flow of gas vthrough the gas conducting means, movable gas operated means for actuating the breech mechanism, and cooperating means on the gas conducting means and barrel for slidably connecting the two and for preventing rotation of the barrel relative to the casing when said gas conducting means is in its normal position, the gasconducting means being movable rearward from normal position to disconnect the same from the barrel to permit rotation of the latter relative to the casing.

3. In a gas operated automatic firearm, the combination of a main casing having breech mechanism therein, a barrel removably connected with the casing at the front thereof. a piston tube having slidable engagement with the casing and movable rearward from its normal position, the said tube being readily detachable from the casing by movement in the forward direction and being longitudinally slottedV near the rear, a removable pin in the casing extending through the slot in the tube to normally maintain the tube in engagement with the casing, a piston in the tube movable rearward by gas pressure to operate the breech mechanism, and means serving when the tube is in'normal forward position to connect it with the barrel to permit gas transmission thereto, the last said means serving upon" rearward movement of the tube to effect disconnection thereof from the barrel and to thus permit the barrel to be removed from the casing.

4. In'a gas operated automatic firearm, the o Vment with the casing, mechanism including a manually operable lever pivoted to the casing and normally extending longitudinally thereof and also including a link pivotally connected with the lever and with the tube, the said mechanism serving upon movement of the lever to move the tube rearward from its normal position, a piston in the tube movable rearward by gas pressure to operate the breech mechanism, and means serving when the tube is in normal forward position to connect it with the barrel to permit gas transmission thereto, the said means serving upon rearward movement of the tube to effect disconnection thereof from the barrel and to thus permit the barrel to be removed from the casing.

5. In a gas operated automatic firearm, the combination of a main casing having breech mechanism therein, a barrel removably connected with the casing at the front thereof, a piston tube adjacent the barrel and having slidable engagement with the casing, .a manually operable lever pivoted to the casing and normally extending longitudinally thereof, the said lever being approximately U-shaped in cross section, a link pivotally connected with the lever and with the tube and normally positioned within the said U-shaped lever, the said link serving upon movement of the lever to move the tube rearward from its normal position, a piston in the tube movable rearward by gas pressure to operate the breech mechanism, and means serving when the tube is in normal forward position to connect it with the barrel to permit gas transmission thereto, the said means servingv upon rearward movement of the tube to effect disconnection thereof from the barrel and to thus permit the barrel to be removed from the casing.

6. In a gas operated automatic firearm, the combination of a main casing having breech mechanlsmetherein including a breech bolt and an extractor projecting forward therefrom, a barrel removably connected with the casing at the front thereof and having a notch at the rear for receiving the extractor, a piston tube adjacent the barrel' and movable rearward from its normal position to a predetermined extent, means associated with the tube and the breech bolt causing the tube upon rearward movement to the said predetermined extent to move the bolt rearward sufnciently to withdraw the extractor from the notch in the barrel, a piston in the tube movable rearward by gas pressure to operate the breech mechanism, and means serving when the tube is in normal forward position to connect it with the barrel to permit gas transmission thereto, the said means serving upon rearward movement of the tube to effect disconnection thereof from the barrel and to thus permet the barrel to be removed from the casing.

'7. In a gas operated automatic rearm, the combination of a main casing having breech mechanism therein including a breech bolt and an extractor projecting forward therefrom, a barrel having a notch at the rear for receiving the extractor, means for removably connecting the barrel with the casing upon relative rotation of the two, a piston tube adjacent the barrel and movable rearward from its normal position to a predetermined extent, means associatedwith the tube and the breech bolt causing the tube upon rearward movement to the said'predetermined extent to move the bolt rearward sufliciently to withdraw the extractor from the notch in the barrel, a piston in the tube movable rearward by gas pressure to operate the breech mechanism, and means serving when the tube is in normal forward position to connect it with the barrel to permit gas transmission thereto, the said means serving upon rearward movement of the tube to effect disconnection thereof from the barrel and to thus permit the barrel to be removed from the casing.

8. In a gas operated automatic firearm, the combination of a main casing having breech mechanism therein including a breech bolt and an extractor projecting forward therefrom, a barrel removably connected with the casing at the front thereof and having a notch at the rear for receiving the extractor, a piston tube adjacent the barrel and having a shoulder thereon, manually operable mechanism for moving the tube rearward from its normal position to a predetermined extent, an operating slide associated with the breech mechanism and having means thereon forengagement by the shoulder on the tube to effect retraction of the slide upon rearward movement of the tube to the said predetermined extent to move the bolt rearward suiiiciently to withdraw the extractor from the notch in the barrel, and means serving when the tube is in normal forward position to connect it with the barrel to permit gas transmission thereto, the said means serving upon rearward movement of the tube to effect disconnection thereof from the barrel and to thus permit the barrel to be removed from the casing.

9. In a gas operated automatic firearm, the combination f a main casing having breech mechanism therein, a barrel removably connected with the casing at the front thereof, a piston tube adjacent the barrel and having slidable engagement with the casing, mechanism including a manually operable lever pivoted to the casing and normally extending longitudinally thereof and also including a link pivotally connected with the lever and with the tube, the said lever and link normally constituting a toggle to lock the piston tube in its forward position and being adapted upon movement of the lever to move the tube rearward from its normal position, a piston in the tube movable rearward by gas pressure to operate the breech mechanism, and

- means serving when the tubeis in normal for- 

